Be/sup 10/ has long been of interest for cosmic ray propagation, because its radioactive decay half-life is well matched to the expected cosmic ray age. Recent beryllium isotope measurements from satellites and balloons have covered an energy range from about 30 to 300 MeV/nucleon/sup 1-3/. At the lowest energies, most of the Be/sup 10/ is absent, indicating a cosmic ray lifetime of order 2 x 10/sup 7/ years and the rather low average density of 0.2 atoms/cc traversed by the cosmic rays. At higher energies, a greater proportion of Be/sup 10/ is observed, indicating a somewhat shorter lifetime. These experiments will be reviewed and then compared with a new experiment covering from 100 to 1000 Mev/nucleon/sup 4/. Although improved experiments will be necessary to realize the full potential of cosmic ray beryllium isotope measurements, these first results are already disclosing interesting and unexpected facts about cosmic ray acceleration and propagation.

Manganin stress gages have been fabricated and used successfully to study initiation and detonation of high explosives. These four-terminal, low-impedance gages have been specially designed and encapsulated to minimize the effects of various gage failure mechanisms. Several candidate dielectric encapsulation materials have been tested in the reactive environment, and of these polytetrafluoroethylene has been chosen. Gage stations are formed by thermally bonding the manganin foil between layers of this dielectric. Gages manufactured in this way have been used to provide stress profiles throughout the region of build-up to detonation in PBX-9404 and TATB.